[Harp-L] the valve "gargle"

[Slim Heilpern]

Hi Vern -

Interesting! 

So to me it sounds like you're saying the increase in sound pressure is causing the windsaver to lift off the reed plate even though the air flow is trying to hold it down? This makes sense to me, but I never thought of it that way before. 

Do you think reed plate waxing would make this less or more of an issue, or have no impact whatsoever? (I've waxed in the past, but of course didn't find it helped with my most common issue, which is the layers of the valves sticking together, so I stopped doing it.)

Incidentally, I have had some success with both the gargle and sticking layers problems by crimping the upper layer to provide more support and less contact. But it seems to be a temporary solution only.

- Slim


> On Jun 13, 2019, at 3:35 PM, Vern <jevern at xxxxx> wrote:
> 
> Slim, your experience is consistent with my theory of the problem.  Introducing some leakage makes the combined embouchure+reed-chamber less resonant.  This allows the steady breath pressure to dominate  the sound pressure peaks.  However, it isn’t a good solution because it is detrimental to tone and responsiveness. 
> 
> As I have said in other posts, I (and Joe)  prefer to use a soft, quiet valve material. You are making the air cavity less resonant. We are making the valve less resonant.  
> 
> It would be desirable to have a hard/springy/stiff valve and a highly resonant air cavity.  However, engineering is the art and science of choosing compromises.
> 
> Vern
> 
>> On Jun 13, 2019, at 7:03 AM, Slim Heilpern <slim at xxxxx> wrote:
>> 
>> Jut picking up one point from the GASKET-VALVE System discussion:
>> 
>> Vern said:
>> 
>> "Not often, but I have experienced a closed valve of hard, springy material standing up and vibrating much as a reed does.  The variations of sound pressure seem to prevail over the more steady breath pressure. This makes a noise that I would describe as a “gargle” instead of a “rattle”."
>> 
>> This is something I've bumped into more and more over the last several years, always on CX-12s. It's taken me a very long time to understand what's happening, but I think I do now. At first it was a huge mystery and I was encountering it on random reeds, usually on draw reeds, regardless of pitch, and only when the airflow is relatively strong. Replacing the valve, regardless of brand or type would not usually solve the issue. Removing the valve always solves the issue for the simple reason that it's the valve that's vibrating (just like in Vern's description above). And reed alignment never seems to be the problem, but it could be a very tiny adjustment or some imperfection in the reed, hard to say. This was happening right out of the box on new CX12s.
>> 
>> One day while struggling with this issue, just trying to save some time, I reassembled the harp with only a few of the reed plate screws, just to test the new valve I had installed and the problem was gone -- not just on one reed but on two others that were having the same problem. So, perhaps if the axe is too airtight this can happen? I ended up not tightening the reedplate screws as much as I would usually do and the problem mostly went away.
>> 
>> Fast forward a couple of years and I purchased a new set of reed plates for one of my CX12s. No 'gargle' sounds at all up and down the axe -- what a relief! However, after several months of playing that axe I decided the slide was rather noisy so I flat sanded the front of the comb and installed one of Brendan's power slides, problem solved.... except that several of the reeds started having the 'gargle' issue. So I loosened a few of the screws a bit and that fixed it. 
>> 
>> So, perhaps, when the tolerances are too tight, the valves aren't strong enough to stay closed?
>> 
>> Or something else?
>> 
>> Thanks,
>> 
>> - Slim
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